import java.sql.*;
import java.util.*;


public class Main {
    public static void main(String[] args) {
        //查询
        //m1();
        //条件查询
        //m2();
        //添加
        //m3();
        //删除
        //m4();
        //修改
        //m5();
        //
        }
        private static void m1() {
            //1.加载驱动
            try {
                Class.forName("com.mysql.cj.jdbc.Driver");

                //2.获取链接(url username password)
                String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
                Connection connection = DriverManager.getConnection(url, "root", "319257rj");
                //if (connection != null) {
                //    System.out.println("连接成功");
                //}
                //3.写sql语句
                String sql = "select * from user";
                //4.预编译sql
                PreparedStatement preparedStatement = connection.prepareStatement(sql);
                //5.如果有参数设置参数

                //6.执行sql语句
                ResultSet resultSet = preparedStatement.executeQuery();
                //7.遍历结果集
                while (resultSet.next()) {
                    int id = resultSet.getInt(1);
                    String name = resultSet.getString(2);
                    String pass = resultSet.getString(3);
                    System.out.println(id + "===" + name + "===" + pass);

                }
                //8.关闭资源
                resultSet.close();
                preparedStatement.close();
                connection.close();

            } catch (ClassNotFoundException e) {
                throw new RuntimeException(e);
            }catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
        private static void m2(){// 1、加载驱动
            try {

                // Scanner
                Scanner sc = new Scanner(System.in);
                System.out.print("请输入你要查询的姓名：");
                String word = sc.next();

                Class.forName("com.mysql.cj.jdbc.Driver");

                // 2、获取连接 (url username password)
                String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
                Connection connection = DriverManager.getConnection(url, "root", "319257rj");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
                // 3、写sql
                String sql = "select * from sys_user where name like ? ";

                // 4、预编译sql
                PreparedStatement preparedStatement = connection.prepareStatement(sql);

                // 5、有参数设置参数
                preparedStatement.setObject(1,"%"+word+"%");

                // 6、执行sql
                ResultSet resultSet = preparedStatement.executeQuery();

                // 7、遍历结果集
                while (resultSet.next()){
                    int id = resultSet.getInt(1);
                    String name = resultSet.getString(2);
                    String pass = resultSet.getString(3);
                    System.out.println(id+"-----"+name+"------"+pass);
                }

                // 8、关闭资源
                resultSet.close();
                preparedStatement.close();
                connection.close();


            } catch (ClassNotFoundException e) {
                throw new RuntimeException(e);
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }



        private static void m3(){  try {

            // Scanner
            Scanner sc = new Scanner(System.in);
            System.out.print("请输入要新增的姓名：");
            String name = sc.next();
            System.out.print("请输入要新增的密码：");
            String pass = sc.next();

            Class.forName("com.mysql.cj.jdbc.Driver");

            // 2、获取连接 (url username password)
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            Connection connection = DriverManager.getConnection(url, "root", "319257rj");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
            // 3、写sql
            String sql = "insert into sys_user(name,pass) values (?,?) ";

            // 4、预编译sql
            PreparedStatement preparedStatement = connection.prepareStatement(sql);

            // 5、有参数设置参数
            preparedStatement.setObject(1,name);
            preparedStatement.setObject(2,pass);

            // 6、执行sql  executeUpdate
            int result = preparedStatement.executeUpdate();

            // 7、结果判断
            if (result > 0) {
                System.out.println("新增成功");
            }

            // 8、关闭资源
            preparedStatement.close();
            connection.close();


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
        }



        private static void m4(){
        // 1、加载驱动
            try {

                Class.forName("com.mysql.cj.jdbc.Driver");

                // 2、获取连接 (url username password)
                String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
                Connection connection = DriverManager.getConnection(url, "root", "319257rj");
//            if (connection != null) {
//                System.out.println("连接成功");
//            }
                // 3、写sql
                String sql = "delete from sys_user where id = ? ";

                // 4、预编译sql
                PreparedStatement preparedStatement = connection.prepareStatement(sql);

                // 5、有参数设置参数
                preparedStatement.setObject(1,"4");

                // 6、执行sql  executeUpdate
                int result = preparedStatement.executeUpdate();

                // 7、结果判断
                if (result > 0) {
                    System.out.println("删除成功");
                }

                // 8、关闭资源
                preparedStatement.close();
                connection.close();


            } catch (ClassNotFoundException e) {
                throw new RuntimeException(e);
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }



}
        private static void m5(){
        //1.加载驱动
            try {
                Class.forName("com.mysql.cj.jdbc.Driver");
                Scanner sc=new Scanner(System.in);
                System.out.println("请输入要修改的序号");
                String id=sc.next();
                System.out.println("请输入要修改的姓名");
                String name=sc.next();
                System.out.println("请输入要修改的密码");
                String pass=sc.next();

                //2.获取链接(url username password)
                String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
                Connection connection = DriverManager.getConnection(url, "root", "319257rj");
                //if (connection != null) {
                //    System.out.println("连接成功");
                //}
                //3.写sql语句
                String sql = "update user set name=? , pass=? where id=?";
                //4.预编译sql
                PreparedStatement preparedStatement = connection.prepareStatement(sql);
                //5.如果有参数设置参数
                preparedStatement.setObject(1,name);
                preparedStatement.setObject(2,pass);
                preparedStatement.setObject(3,id);
                //6.执行sql语句
               int result=preparedStatement.executeUpdate();
                //7.遍历结果集
                if(result>0){
                    System.out.println("修改成功");
                }
                //8.关闭资源

                preparedStatement.close();
                connection.close();

            } catch (ClassNotFoundException e) {
                throw new RuntimeException(e);
            }catch (SQLException e) {
                throw new RuntimeException(e);
            }

        }


    }
